Maximum level detector

ABSTRACT

This device for detecting the maximum predetermined level of a liquid in a vessel, for example a bath tub, and warning the user when this level is attained, comprises essentially two elements, i.e., a bottom or reference element retained by gravity at the bottom of the vessel, and a float element remaining by buoyancy at the level of the liquid, and means interconnecting these two elements. These means are either telescopic or flexible, for example in the form of a nylon cord, and the float encloses a circuit comprising a source of current, a switch and a sound and/or luminous signal device. The switch is closed when the float attains the maximum preset level.

United States 4 Patent [191 Staempfli MAXIMUM LEVEL DETECTOR [76]Inventor: Jackie Staempfli, 20, Rue du Commandant Mouchotte 75, Paris,France 221 Filed: June 11, 1971 211 App]. No.: 152,110

[52] US; Cl 340/245, 73/308, 73/309, 73/3225, 340/244 D, 340/244 R [51]Int. Cl. G08b 21/00 [58] Field of Search 340/245, 244 D, 244 R; 73/308,309, 314

[56] References Cited UNITED STATES PATENTS 892,425 7/1908 Homer 340/244B 3,545,272 12/1970 McGill.....' 340/244 D [451 Jan. 15,1974

Primary ExaminerThomas B. Habecker Attorney-Robert E. Burns and EmmanuelJ. Lobato [5 7 ABSTRACT This device for detecting the maximumpredetermined level of a liquid in a vessel, for example a bath tub, andwarning the user when this level is attained, comprises essentially twoelements, i.e., a bottom or reference element retained by gravity at thebottom of the vessel, and a float element remaining by buoyancy at thelevel of the liquid, and means interconnecting these two elements. Thesemeans are either telescopic or flexible, for example in the form of anylon cord, and the float encloses a circuit comprising a source ofcurrent, a switch and a sound and/or luminous signal device. The switchis closed when the float attains the maximum preset level.

3 Claims, 5 Drawing Figures PATENTEB JAN I 5 I974 'SHEU 1 OF 4 PMENTED N1 51914 3'. 786.464

sum 3 or 4 MAXIMUM LEVEL DETECTOR BACKGROUND OF THE INVENTION Thepresent invention relates to devices for detecting the level of a liquidcontained in a vessel, notably a bath tub, of the type comprising meansadapted to emit a signal for warning the user of the bath tub when thewater level therein is at the maximum level preset by the user himself.

DESCRIPTION OF THE PRIOR ART In all bath tubs, even of the latest types,there is an overflow safety outlet but this outlet permits the escape ofonly a moderate and insufficient outflow in comparison with the outputof the supply faucets. Therefore, except when a tub is filled at a very'moderate water output rate, the outlet orifice will only retard the timewhen the water will flow over the top edge of the tub, so that theseoverflows cannot be considered as constituting an efficient protectionagainst bathroom floods.

It is already known to use a device for detecting the liquid level in abath tub, this device comprising a wall fixture carrying an electriccontact and a rigid telescopic arm dipping in the top aperture of thebath tub, the lower element of this arm is brought by the user down toa' predetermined level so that when the water rises to the level of thiselement it closes an electric switch. Now this detector is cumbersome,has a poor aesthetic appearance and lacks flexibility. Furthermore, itis objectionable in that it lies almost entirely outside the bath tuband is secured as a permanent fixture to the wall of the bathroom.

It is also known to provide a device for detecting the level of thewater contained in a; bath tub, wherein a float is adjustably mounted ona rod and adapted to ac tuate through this rod an electric switchsecured to the top edge of the tub. Now this device is not only ofscarcely attractive appearance, and cumbersome, but constitutes a sourceof discomfort for the user; furthermore, a relatively long time isnecessary for mounting and removing this device to and from the edgeof'the tub. i v

Another known device comprises a float adapted to follow the variationof a liquid mass in a tank between a minimum level and a maximum level,and at the same time to control theopening of a valve for supplyingliquid to the tank and another valve for draining this liquid outtherefrom. Now this device is responsive to the successivepo'sitionsassumed by the float in relation to the bottom and cover of said tank,but its flexibility is objectionable in that the device is notadjustable according to the operators requirements.

SUMMARY OF THE INVENTION It is the essential object of the presentinvention to avoid this serious inconvenience by providing a maximumwater level detector for use in all bath tubs, this detector beingadapted to emit a signal forwarning the user if he stays in another roomor pays no attention to the tub filling process. a

This device for detecting the level of a liquid contained in a vessel,notably a bath tub, comprises a first element floating on the surface ofthe liquid, a second reference element is retained at the bottom of thevessel. An electric circuit means is enclosed in the first element andcomprises: a sound and/or luminous signal device, a source of electriccurrent for energizing said signal device and releasing an alarm signal,and finally a normally open switch inserted between the electric currentsource and the signal device. Adjustable means interconnect the firstfloating element and the second reference element. The adjustable meansare vertically adjustable and adapted to control the closing of saidswitch when the distance between the levels of said elementsrespectively has attained a predetermined value corresponding to themaximum level not to be exceeded in the vessel concerned.

BRIEF DESCRIPTION OF THE DRAWINGS Typical forms of embodiment of thisinvention will now be described by way of example with reference to theaccompanying drawings in which:

FIG. 1 is a diagrammatic vertical view showing a first form ofembodiment of the detector of this invention, wherein the two elementsare interconnected by a rigid telescopic arm;

FIG. 2 illustrates the mode of operation of the device in FIG; 1;

FIG. 3 is a modified form ofembodiment of the detector of thisinvention, and

FIG. 4 and 5 are an elevational view and a vertical axial section,respectively, showing another form of embodiment of the detector whenthe two elements are interconnected by a flexible wire or cord, theseFigures corresponding to the inoperative and operative positions,respectively of the device.

DESCRIPTION or THE PREFERRED EMBODIMENTS Referring first to FIG. 1, thedetector 1 comprises a first floating element 2 and a second element 3called hereinafter the reference element, which is retained by gravityat the bottom of the tub. The bottom is therefore, a reference datumThese two elements 2 and 3 are rigidly interconnected by a telescopictubular rod 4 provided if desired, like the lower portion of thefloating element 2, with a scale divided into centimeters or inches, asshown by the reference numeral 5 in FIG. 2.

By properly adjusting the length of the telescopic rod 4 in relation tothe floating element 2, it is thus possible to adjust with precision themaximum permissible water level in the tub. In fact, as shown in FIG. 2,the detector 1 occupies successive positions as a consequence of theincreasing buoyancy of the water 6. The weight 3 remains in the bottom 7of the tub while the first element 2 remains constantly at the waterlevel. Thus, the detector 1 having initially a substantially horizontalposition is moved to a substantially vertical position. When thedetector 1 is in this substantially vertical position a normally openswitch is closed to supply energizing current to an electric circuitcomprising a In the detector of FIG. 1 the switch inserted between thepower source 8 and the warning or signal device 9 consists of a smallcup 10 of at least partially spherical configuration, in which a mercurydrop 11 has been placed. When the detector 1 is in a substantiallyvertical position the mercury 11 will close the gap between a pair ofelectrodes 12 and 13 welded to the lower portion of cup 10. If desired,the upper of floating element 2 of detector 1 is provided with athermometer 14.

FIG. 3 illustrates a first modified form of embodiment of the detectorof this invention. In this alternate form of embodiment the firstfloating element 2 incorporating the electrical circuit and theancillary means, and the second element or immersed weight 3, arerigidly interconnected as follows the floating element 2 carries aninternal tubular member 22 in which a ball 23 is adapted to travelwithout play this ball 23 is prevented from falling in the tube 22 by arod 24 coaxial therewith and adapted to slide freely through an orifice25 formed at the lower end of the case 21 of floating element 2, thelower end of rod 24 being constantly kept in contact with the bottom 7of the bath tub by a weight 3 attached to said lower portion. Ifdesired, a seal 26 is provided for preventing water from rising into thefirst floating element 2. The rod 24, like the rod 4 of the device shownin FIG. 1, is of telescopic type and preset to a length such that whenthe water rises to a predetermined level in the tub the rod supportedball 23 engages simultaneously the pair of electrodes 27 and 28, thusclosing the electrical circuit supplied from the power source 8 toenergize the warning or signal device 9.

Another modified and particularly advantageous form of embodiment of thedevice of this invention is illustrated in FIGS. 4 and 5 of thedrawings. The first floating element 2 consists in this case of hollowspherical member and the reference immersed element 3 connected by meansof a flexible cord 29, for example of nylon, to the float 2, is retainedon the bottom 7 of the bath tub by gravity, for example by embeding aring 30 of high-density metal in said element 3. The flexible cord 29constitutes an advantageous cheaper substitute for the telescopic rod 4or 24 of the preceding forms of embodiment and is adjustable in lengthby means of an elastomeric block 31, for example of rubber, holding thecord 29 by friction along its vertical axis, so as to determine on theone hand the length of the free upper portion of said cord 29 andtherefore the maximum level which the liquid may safely attain in thetub, and on the other hand, the length of the useful cord section 32.The cord 29 is attached at one end to the immersed weight 3 at any pointand preferably centrally thereof, and on the other hand to the floatZsubstantially at the highest possible point of this float when thelatter is in its position of equilibrium as shown in FIG. 4.

Under these conditions from the bottom 7 of the tub on which it wassupported by its legs 36, the float 2 rises gradually vertically whilepreserving its initial position which, by construction, is determined asconstituting the position of equilibrium by buoyancy. As the float 2rises in the tub, the flexible nylon cord 29 is moderately tensioned andeventually, when the float 2 attains the maximum, preset or permissiblelevel, the cord 29, of which the upper excess length has been carefullycalculated, will be tensioned to a greater degree and thus cause thefloat to start a slow overturning movement about its center of gravity,as shown by the arrow 37 of FIG. 4.

Then the float 2 will tend to assume another position of equilibriumwhich is symmetrical to that obtaining under normal or free buoyancy,since it is retained through its anchoring point 35 by the flexibletensioned cord 29 (FIG. 5). When a certain angle of tilt of the float isattained, the mercury drop 11 which was initially in the bottom of thecup 10, i.e., in position 38 shown in dash and dot line, closes thecontact between the two electrodes 12 and 13, and thus causes theenergization of the signal device in order to warn the user of the bathtub that the desired water level has been attained therein and that thewater supply faucets must be turned off.

Of course, this invention should not be construed as being strictlylimited by the specific forms of embodiment described and illustratedherein, since many modifications could be brought thereto withoutdeparting from the basic principle of the invention as those skilled inthe art will readily understand. Thus, more particularly, the detectorof FIGS. 4 and 5, constitutes the preferred form of embodiment onaccount of its simplified construction, good appearance and originality.Briefly, in actual practice, this detector may be constructed as follows(FIGS. 4 and 5) z the floating spherical element 2 is obtained bysuperposing three compartments, namely a lower compartment 39 oftransparent plastic material, an intermediate compartment 40 and anupper compartment 41 both made of opaque plastic material. Enclosed inthe upper compartment 41 are the dry batteries 8 constituting the powersource, the cup 10 and the electrodes 12 and 13; this assembly iscovered with a floor" forming plate 42 and the necessary water-tightnessof the chamber 43 thus obtained is provided for by an O-ring 44. In theintermediate compartment 40 a sound warning device 9 is enclosed thisdevice 9 is connected on the one hand to the battery 8 and on the otherhand to one of the two electrodes, in this case electrode 12. The soundsignal emitted by the warning device 9 when the mercury drop 11 bridgesthe gap between the electrodes 12 and 13 is facilitated considerably onthe one hand by the presence of a flat diaphragm 33 disposedsubstantially at the level of the lower plane of the intermediatecompartment 40, and on the other hand by the presence of perforations 34formed in the upper portion of the lower compartment 39. For reasons ofaesthetics and convenience the thermometer 14 is disposed in the visibleportion of float 2 in the operative position thereof, i.e., thethermometer 14 is disposed in the compartment 39 of transparent plasticmaterial.

What I claim and desire to secure by letters patent is:

1. An alarm device for detecting the level of a varying level of liquidin a vessel comprising, a reference means immersible in liquidpositioned in use in a vessel for determining a reference datum relativeto which a predetermined level of a varying level of liquid increasingin volume in the vessel is to be detected and its attainment indicated,a float means for floating freely on the surface of the liquid inoperation as the liquid level changes, means connecting said referencemeans and said float means to establish said predetermined level of theliquid as a function of a preselected distance between said referencemeans and said float means, an alarm means in said float means coupledto and actuated by said connecting means for sensing when the relfloatmeans comprises means defining variable telescopic means.

3. An alarm device for detecting the level of a varying level of liquidin a vessel according to claim 1, in which said means connecting saidreference means and float means comprises variable means for settingindividually different predetermined selected levels of said liq uid tobe detected and indicated.

1. An alarm device for detecting the level of a varying level of liquidin a vessel comprising, a reference means immersible in liquidpositioned in use in a vessel for determining a reference datum relativeto which a predetermined level of a varying level of liquid increasingin volume in the vessel is to be detected and its attainment indicated,a float means for floating freely on the surface of the liquid inoperation as the liquid level changes, means connecting said referencemeans and said float means to establish said predetermined level of theliquid as a function of a preselected distance between said referencemeans and said float means, an alarm means in said float means coupledto and actuated by said connecting means for sensing when the relativedistance between said reference means and said float means correspondsto said preselected distance and thereby is representative of theattainment of said predetermined level and means responsive to thelast-mentioned means for energizing said alarm means to indicate theattainment of said predetermined liquid level.
 2. An alarm device fordetecting the level of a varying level of liquid in a vessel accordingto claim 1, in which said means connecting said reference means and saidfloat means comprises means defining variable telescopic means.
 3. Analarm device for detecting the level of a varying level of liquid in avessel according to claim 1, in which said means connecting saidreference means and float means comprises variable means for settingindividually different predetermined selected levels of said liquid tobe detected and indicated.